Spray-gun head



Jan. 3, 1928. 1,655,253

M, J. BIN KS SPRAY GUN HEAD Filed Dec 17. 1926 Patented Jan. 3, 1928.

UNITED STATES v 1,655,253 PATENT OFFICE.

MELVIN J. BINKS, OF OAK PARK, ILLINOIS, ASSIGNOR TO BINKS SPRAY EQUIPMENT 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SPRAY-GUN HEAD.

Application med December 17, 1928. Serial 1T0. 155,464.

My invention relates to spraying applia-nces employed for projecting liquids-such as coating materials-inthe form of a finely divided spray, and particularly to the types 5 of such appliances in which an initially cylindrical stream of the projected liquid is converted by opposed jets of air'into'a fiattened spray.

In such socalled spray guns -the commercial efiiciency and the eliminating of a later touching up of the coated objects'depends considerably on an accurate alining of the several parts of the head of the appliances. That is to say, the initially projected cylindrical stream of the liquid coating material should be exactly coaxial with the tubular sheath of air projected around this liquid stream, and in a medial plane between the flattening jets of air. With the spray guns now in common use, this needed alining requires adegree of accuracy not attained in ordinary machine shop practice. To overcome this difficulty, my invention provides a spray gun head construction in which three operative head portions seat concentrically on one another to insure their'accurate alin- D nother difiiculty commonly encountered with spray guns is due to the rebound of sprayed coating material from the objectwhich ,is being coated. With the usual head constructions, some of this rebounding material is apt to attach itself to parts of the head whereit may pile up so as to clog the lateral .air outlets and so as to deflect air from these outlets, thereby seriously disturbing the desired spray formation. Moreover, currents of air ay afterwards detach it in more dense form, thereby producing spots 40 which mar the desired uniformity of the coating. My present invention provides a gun head shaped to overcome this difiiculty' also.

Moreover, my invention aims to provide a spray gun head construction which will alsobe easy to manufacture and assemble, easy to keep clean and which will afford air pas-' sages of such proportions as not to require a wasteful amount of air pressure. Still further and also'more detailed objects will appear from the following specification and from the accompan ing drawings, in which Fig. 1 is a centra vertical and longitudinal section through the forward portion of a spray gun embodying my invention.

Fig. 2 is a front elevation of the head parts of Fig. 1.

Fig. 3 is a horizontal section through the air nozzle and the air confining collar of the embodiment shown in Fig. 1.

F g. 4 is a plan view of the air nozzle.

F g. 5 1s a rear elevation of the air nozzle. Fig. 6 1s a side elevation of the liquid nozzle.

Fig. 7 is a section, similar to portions of Fig. 1, but showing a difierentconstruction of the air nozzle and of the liquid nozzle. namely one in which the longitudinal grooves for supplying air to the annular air outlet are formed in the liquid nozzle.

Referring first to the embodiment of Figs. 1 to 6 inclusive, the drawings show parts of a spray gun in which the body member comprises a body 1 which is initially manufactured separately from the liquid nozzle 2 and afterwards threadedly connected to the latter. The gun body 1 has the usual longitudinal liquid supply passage 3 and the rear end-of the liquid nozzle is threaded into the forward end of this passage, so as to have the said passage open into the bore 4 of the liquid nozzle for supplying li uid which enters through an inlet bore 5. en the liquid nozzle is threadedly attached to the gun body, the bore of the nozzle is in approximate axial alinement with the passage 3 and with a needle valve 6. This needle valve has a pointed tip extending into the diametrically contracted forward end portion 4 of the bore of the liquid nozzle, so as to close or 0 en this outlet portion 4* of the liquid nozz e when the needle is moved longitudinally in the usual manner.

Thepart of the liquid nozzle behind the outlet portion and in front of the gun body has a forwardly tapering frustro-conical exterior which affords a tightly fitting seat for the correspondingly tapered rear portion of the bore 7 of the air nozzle18. This air nozzle'bore is contracted at its forward end ,to a cylindrical outlet portion 7 which is of somewhat larger diameter than the tubular outlet portion 4' of the liquid nozzle and which surrounds the latter portion so as to leave; an intervening annular port for discharging an annular sheath of compressed air around the initially cylindrical stream of liquid which isdischarged through the bore of the outlet portion 4 of the liquid nozzle.

, pair of The periphery of the airnozzle has a generally frustro-conical and forwardly tapering form which tightly fits the correspondingly tapering bore of an air confining collar 8, which collar has its rear end abut-ting against the forward end of the gun body and has the said rear collar end radially thickened to alford an outwardlyprojecting flange 9. This flange is housed by a re taining ring 10 which has its rearward portion threaded upon the gun body and which has at its forward end an inwardly directed flange 11 engaging the collar flange 9 so as to, clamp the collar against the gun body when the ring 10 is threadedly attached to the gun body.

The air nozzle is considerably shorter than the collar 8, so as to leave a large annular air chamber 12 around a part of the liquid nozzle, to which chamber compressed air is supplied by an air passage 13 in the gun body. This air chamber is connected to the annular space between the outlet bore portion 7 of the air nozzle and the outlet end of the liquid nozzle by passages which desirably are grooves along one of the interfitting surfaces of the liquid nozzle or the air nozzle. These passages are shown in Figs. 1 and 3 as longitudinal grooves 14 formed in the frustro-conical portion of the bore of'the air nozzle and extending from the rear end of the air nozzle to a point forward of the correspondingly tapered portion of the liquid nozzle.

To furnish the flattening air jets, I provide the eriphery of the air nozzle with a diametrically opposite longitudinal grooves 15 open at the rear end of the air nozzle but terminating somewhat back of the forward end of the air nozzle. Then I provide air outlet ports respectively leading from the forward ends of these grooves, such as the small diametered bores 16. each of which bores extends through a forwardly projecting lug 17 which allows a suflicient length to the bore to secure an accurate directin of the jet of air projected through it. These bores slope forwardly toward the axis of the air nozzle and have their axes intersecting the said nozzle axis at a common tion. By making the collar flange 9 a little smaller than the bore of the ring 10. and by making the ring flange 11 larger in bore than the outside diameter of the collar 8, I permit such shifting of the collar transversely of the axis of the liquid passage 3 memes as may be needed to-permit the said alining of the nozzles. At the same time, the length of the needle valve 6 permits this to spring so as to compensate for a shifting in the position of the nozzle outlet which this valve controls. Hence my simple construction allows me to secure the desired alining while only requiring ordinary machine shop accuracy.

To prevent the deposit of rebounding paint or otherliquid material on the front parts of my spray gun, I make the major portions of the front end of the air nozzle V-shaped in a section taken at right angles to the common plane in which the axes of the air jet ports 16 are disposed, and make the entire front end of the collar of a similar shape, as shown in Figs. 3 and 4. lVith the end thus formed, liquid rebounding against it from the object which is being coated will be laterally deflected as shown by the dotted lines 19 in Fig. 3, instead of having an opportunity to attach itself to either the air nozzle or the forward end of the collar. Moreover, the blasts of air issuing both from the annular air port and through the bores 16' will induce air currents sweeping along these sloping front end surfaces, thereby preventing rebounding liquid from reaching the relatively small flat end portion 20 between the lugs 17, hence this part can be left flat. To keep the tapering end surfaces of the air nozzle and collar in alinement, I provide these parts with means for preventing their relative rotation, such as av pin 21 driven into an edge portion of the air nozzle and slidably entering a groove 22 in the collar, as shown in Fig. 3.

However, I do not wish to be limited to the details of the construction and arrangement above described, since many changes might be made without departing either from the spirit of my invention or from the appended claims. For example, Fig. 7 shows an air nozzle 24 with an ungrooved frustro-conical rear bore portion 25 which fits the tapering exterior part 26 of a liquid nozzle 27 In this case, longitudinal grooves 28 extend for the entire length of this nozzle part to supply air to the annular port between the nozzle outlet 4 and the outlet bore 7 of the air nozzle.

I claim .as my invention:

1. In a spray gun, a body, a li uid nozzle projecting forwardly from it an having a small diametered forward tip and a rearwardly flaring frustro-conical portion behind the said tip, an air nozzle having a forward portion freely housing the said tip and a main bore portion fitting the said flaring portion of the liquid nozzle, the air nozzle.

having its rear end forwardof the body to provide an air space therebet'ween, the body having an air duct leading to the said air space and a liquid passage leading to the ill) asaaea bore of the liquid nozzle, there being air passages connecting the said air space with the space between the said'tip and the forward portion of the air nozzle, the air nozzle having a forwardly tapering peripheral portion; and a collar having a forwardly tapering bore portion fitting the said peripheral portion of the air nozzle to clamp the latter upon the liquid nozzle, and means for detachably securing the collar to the body, the said means being arranged to permit the collar to shift transversely of its axis, the air nozzle having rearwardly. diverging straight air ports extending into it from its forward end, there being air passages connecting the rear ends of the said ports with the said air space,

2. A spray gun as per claim 1, in which the last named air passages consist of longitudinal grooves formed in the periphery of the air nozzle, the said grooves being open at their rear ends and terminating behind the front of the air nozzle.

3. In a spray gun, an air nozzle having a central air port and having a pair of supplemental ports disposed at opposite sides of the central port with the axes of the three ports in a common plane, the air nozzle having the major portions of its forward end wedge shaped with the edge of the wedge disposed in the said plane.

4. In a spray gun, an air nozzle having a central air port and having a pair of supplemental p'orts disposed at opposite sides of the central port with the axes of the three ports in a common plane, the air nozzle having the major portions of its forward end wedge shaped with the edge of the wedge disposed in thesaid plane and with the sides of the wedge at angles of about 45 degrees from that plane. 7

5. In a spray gun an air nozzle having a central air port and having apair of forwardly projectinglugs through which supplemental air ports extend, the axes of the three ports being in a common plane; the major portion of the front end of the air nozzle being wedge'shaped, with the edge of the wedge disposed in the said plane and extending along both of the said lugs.

6. In a spray gun, an air nozzle having a central air port and having a pair of forwardly projecting lugs through which supplemental air ports extend, the axes of the three ports being in a common plane; the major portion of the front end of the air nozzle being wedge shaped, with the edge of the Wedge disposed in the said plane and extending along both of "the said lugs; a retaining collar fitted upon the air nozzle and having its entire front end wedge shaped in alinement with the said major front end portion of the air nozzle, and means operatively interposed between the air nozzle and the collar to prevent relative rotation thereof.

7. A spray gun as per claim 6 in which the front end surfaces of the said wedge shaped forward end parts of the air nozzle and of the collar are plane surfaces disposed at angles of approximately 45 degrees to the said common plane of the port axes.

Signed at Chicago, Illinois, December MELVIN J. BINKS. 

